Dependence of fluidity of human erythrocyte membranes on their methods of preparation.

At intermediate temperatures, erythrocyte membranes prepared under isotonic condition were found to be more fluid than membranes prepared under hypotonic condition. Below 17 degrees C and above 30 degrees C, however, no difference in fluidity was observed. The lower steady state diphenylhexatriene fluorescence anisotropy value observed for isotonic membranes was not due to the use of saponin in their preparation but to the loss of membrane-associated proteins extractable by isotonic buffered saline.